1. Field of the Invention
The present invention relates to a flow meter.
2. Background Art
In a chip mounter, etc. for sucking an IC chip in a vacuum and holding and conveying the IC chip, it is judged whether the IC chip is appropriately sucked and held by monitoring the existence of an air flow of a vacuum flow path. When a compact and light flow meter is mounted to the head of such a chip mounter requiring a high speed operation and the existence of the air flow is monitored, high speed responsibility is more important than the accuracy of a flow rate. In patent literatures 1 and 2, the high speed responsibility is improved by devising the structure of a flow sensor.
[Patent literature 1] JP-A-6-66612
[Patent literature 2] JP-A-2003-240618
However, a fluid has inertia even when any high speed sensor is used. Accordingly, the fluid is intended to be continuously flowed within the flow meter even when the flow path is interrupted. Otherwise, the fluid is intended to stay in the same place even when the flow path is opened. Therefore, a problem exists in that a change in the flow velocity of a measured fluid within the flow meter is delayed and delay is caused in detection.